83 lines
2.6 KiB
ReStructuredText
83 lines
2.6 KiB
ReStructuredText
.. SPDX-License-Identifier: GFDL-1.1-no-invariants-or-later
|
|
.. c:namespace:: V4L
|
|
|
|
.. _VIDIOC_G_STD:
|
|
|
|
**************************************************************************
|
|
ioctl VIDIOC_G_STD, VIDIOC_S_STD, VIDIOC_SUBDEV_G_STD, VIDIOC_SUBDEV_S_STD
|
|
**************************************************************************
|
|
|
|
Name
|
|
====
|
|
|
|
VIDIOC_G_STD - VIDIOC_S_STD - VIDIOC_SUBDEV_G_STD - VIDIOC_SUBDEV_S_STD - Query or select the video standard of the current input
|
|
|
|
Synopsis
|
|
========
|
|
|
|
.. c:macro:: VIDIOC_G_STD
|
|
|
|
``int ioctl(int fd, VIDIOC_G_STD, v4l2_std_id *argp)``
|
|
|
|
.. c:macro:: VIDIOC_S_STD
|
|
|
|
``int ioctl(int fd, VIDIOC_S_STD, const v4l2_std_id *argp)``
|
|
|
|
.. c:macro:: VIDIOC_SUBDEV_G_STD
|
|
|
|
``int ioctl(int fd, VIDIOC_SUBDEV_G_STD, v4l2_std_id *argp)``
|
|
|
|
.. c:macro:: VIDIOC_SUBDEV_S_STD
|
|
|
|
``int ioctl(int fd, VIDIOC_SUBDEV_S_STD, const v4l2_std_id *argp)``
|
|
|
|
Arguments
|
|
=========
|
|
|
|
``fd``
|
|
File descriptor returned by :c:func:`open()`.
|
|
|
|
``argp``
|
|
Pointer to :c:type:`v4l2_std_id`.
|
|
|
|
Description
|
|
===========
|
|
|
|
To query and select the current video standard applications use the
|
|
:ref:`VIDIOC_G_STD <VIDIOC_G_STD>` and :ref:`VIDIOC_S_STD <VIDIOC_G_STD>` ioctls which take a pointer to a
|
|
:ref:`v4l2_std_id <v4l2-std-id>` type as argument. :ref:`VIDIOC_G_STD <VIDIOC_G_STD>`
|
|
can return a single flag or a set of flags as in struct
|
|
:c:type:`v4l2_standard` field ``id``. The flags must be
|
|
unambiguous such that they appear in only one enumerated
|
|
struct :c:type:`v4l2_standard` structure.
|
|
|
|
:ref:`VIDIOC_S_STD <VIDIOC_G_STD>` accepts one or more flags, being a write-only ioctl it
|
|
does not return the actual new standard as :ref:`VIDIOC_G_STD <VIDIOC_G_STD>` does. When
|
|
no flags are given or the current input does not support the requested
|
|
standard the driver returns an ``EINVAL`` error code. When the standard set
|
|
is ambiguous drivers may return ``EINVAL`` or choose any of the requested
|
|
standards. If the current input or output does not support standard
|
|
video timings (e.g. if :ref:`VIDIOC_ENUMINPUT`
|
|
does not set the ``V4L2_IN_CAP_STD`` flag), then ``ENODATA`` error code is
|
|
returned.
|
|
|
|
Calling ``VIDIOC_SUBDEV_S_STD`` on a subdev device node that has been registered
|
|
in read-only mode is not allowed. An error is returned and the errno variable is
|
|
set to ``-EPERM``.
|
|
|
|
Return Value
|
|
============
|
|
|
|
On success 0 is returned, on error -1 and the ``errno`` variable is set
|
|
appropriately. The generic error codes are described at the
|
|
:ref:`Generic Error Codes <gen-errors>` chapter.
|
|
|
|
EINVAL
|
|
The :ref:`VIDIOC_S_STD <VIDIOC_G_STD>` parameter was unsuitable.
|
|
|
|
ENODATA
|
|
Standard video timings are not supported for this input or output.
|
|
|
|
EPERM
|
|
``VIDIOC_SUBDEV_S_STD`` has been called on a read-only subdevice.
|